Field of the Invention
This invention relates to an image pickup apparatus, its control apparatus, and its control method.
Description of the Related Art
In some image pickup apparatuses such as a digital camera and a digital video camera, pixels of the whole or apart of an image sensor have distance measuring function. Such image pickup apparatus includes a plurality of photoelectric conversion portions for each pixel, and detects a distance to an object by a phase-difference method. For example, Japanese Patent Laid-Open No. 2014-74891 describes an image pickup apparatus that generates an image and distance distribution corresponding to the image (hereinafter referred to as “distance map”) using the above mentioned technique.
Generating a distance map, however, requires a correlation calculation of a focus detection signal obtained from each photoelectric conversion portion for each pixel, and therefore the calculation load on a calculation circuit increases. It has a problem that processing of a calculation circuit is delayed, etc.